is, he considered that what seem, to us
to be qualitative differences in things, _e.g._ hot or cold, sweet or
sour, green or yellow, are only resulting impressions from different
shapes, or different arrangements, or different modes of presentation,
among the atoms of which things are composed.

Coming now to that which _is_, Democritus, as against the Eleatics,
maintained that this was not a unity, some one immovable, unchangeable
existence, but an innumerable number of atoms, invisible by reason of
their smallness, which career through empty space (that which _is
not_), and by their union bring objects into being, by their separation
bring these to destruction. The action of these atoms on each other
depended on the manner in which they were brought into contact; but in
any case the unity of any object was only an apparent unity, it being
really constituted of a multitude of interlaced and mutually related
{77} particles, and all growth or increase of the object being
conditioned by the introduction into the structure of additional atoms
from without.

[149]

For the motions of the atoms he had no anterior cause to offer, other
than necessity or fate. They existed, and necessarily and always had
existed, in a state of whirl; and for that which always had been he
maintained that no preceding cause could legitimately or reasonably be
demanded.

[150]

Nothing, then, could come out of nothing; all the visible structure of
the universe had its origin in the movements of the atoms that
constituted it, and conditioned its infinite changes. The atoms, by a
useful but perhaps too convenient metaphor, he called the _seeds_ of
all things. They were infinite in number, though not infinite in the
number, of their shapes. Many atoms were similar to each other, and
this similarity formed a basis of union among them, a warp, so to
speak, or solid foundation across which the woof of dissimilar atoms
played to constitute the differences of things.

[151]

Out of this idea of an eternal eddy or whirl Democritus developed a
cosmogony. The lighter atoms he imagined flew to the outmost rim of
the eddy, there constituting the heavenly fires and the heavenly
aether. The heavier atoms gathered at the centre, forming successively
air and water and the solid earth. Not that there was only one such
{78} system or world, but rather multitudes of them, all varying one
from the other; some without sun or moon, others with greater